Application of silica before sowing negatively affects growth and survival of rice following submergence

Issue Date

8-2011

Abstract

Vast rainfed lowland areas in Asia periodically experience flash floods that adversely affect the survival and productivity of rice (Oryza sativa L.) . Progress has been made in developing tolerant germplasm, but fewer efforts have been devoted to developing proper management options for flood-prone areas. The effects of silica application (600 kg SiO₂ha¯¹) in soil 1 d before sowing on the growth and survival of 21-d-old seedlings submerged for 12 d were evaluated in two experiments. Four contrasting cultivars, tolerant IR49830-7-1-2-3 and Swarna-Sub1 and intolerant IR42 and Swarna, were used. Dry weight , chlorophyll concentration, shoot length, and non-structural carbohydrates were measured before and after complete submergence, and survival was determined 21 d after de-submergence. Survival of all genotypes decreased substantially in Si-treated seedlings, with the tolerant genotypes showing consistently higher survival. No significant interaction was observed between Si treatment and genotypes varying in tolerance of flooding. Si-treated seedlings had lower root dry weight and root-shoot biomass ratio, and greater chlorophyll concentration before submergence. Greater shoot elongation and higher reduction in levels of chlorophyll and non-structural carbohydrate concentrations during complete submergence and greater chlorophyllase activity 1 d after de-submergence were observed in Si-treated seedlings than in the control, and similarly in the sensitive genotypes than in tolerant ones. Survival was negatively correlated with chlorophyll degradation, extent of non-structural carbohydrate depletion, and shoot elongation during submergence. Apparently, excessive Si application in soil 1 d before sowing has negative consequences on seedling growth and survival after complete submergence at vegetative stage in rice.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

36

Issue

2

Page

1-11

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables/graphs

Language

English

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